Synthetic porphyrins-(tetraphenylporphin analogs)-with various functional groups (acidic, basic, neutral) are made. Metal complexes (copper, zinc, nickel, cobalt, manganese, chromium and iron) are prepared from these porphyrins. The iron complexes are studied for their binding with various ligands-oxygen, carbon monoxide, nitrogen oxides, etc. - in the gas phase at low temperature in an inert matrix. The zinc complexes are used to bind with nitrogen ligands in solution. The rate of copper incorporation in free base porphyrins are also studied. The water soluble porphyrins are studied for binding with specific proteins, binding with DNA, localization into tumor tissues in experimental animals and also effects on fibrinogen action. All these porphyrins are studied spectroscopically - infrared, UV-visible, NMR, Raman and ESR.